| cis configuration | <molecular biology> The configuration of an organic molecule containing a double bond between two carbon atoms, where the largest, most complex R groups are on the same side: H H \ / C=C / \ H3C CH3 -OR-The configuration of an organic molecule containing a ring, where the largest, most complex R groups are on the same side: H H | ___ \ / | // \\ [ring viewed edge-on] | \___/ / \ | /---\ H3C CH3 | H3C CH3. A genetics term meaning an event or a gene whose action occurs on the same chromosome. Two mutations in different genes coding for the same phenotype which are on the same chromosome (as opposed to the trans configuration where each homologue has one of the mutations). Compare: trans configuration. (11 Jan 1998) |
|---|---|
| cis dominance | <molecular biology> When a gene or promoter affects only gene activity in the DNA duplex molecule in which it is placed the effect is referred to as cis, as opposed to trans effects when a gene or promoter on one DNA molecule can affect genes on another DNA molecule. Cis dominance is seen only when the appropriate pair or set of genes are all cis to each other. (18 Nov 1997) |
| cis-isoprenyltransferase | <enzyme> Cis-isoprene units of dolichyl monophosphate are added to trans,trans-farnesyl pyrophosphate using isopentenyl pyrophosphate as donor; from embryonic rat brain Registry number: EC 2.5.1.- Synonym: long-chain cis-isoprenyltransferase (26 Jun 1999) |
| cis-prenyl transferase | <enzyme> Involved in dolichol biosynthesis Registry number: EC 2.5.1.- Synonym: cis-prenyltransferase (26 Jun 1999) |
| cis-toluene dihydrodiol dehydrogenase | <enzyme> Nad specific dehydrogenase; reduces ring structure Chemical name: 1,2-dihydroxy-3-methylcyclohexa-3,5-diene dehydrogenase Registry number: EC 1.3.- Synonym: ctd dehydrogenase (26 Jun 1999) |
| cis-trans-isomerases | <enzyme> Enzymes that catalyze the rearrangement of geometry about double bonds. Registry number: EC 5.2 (12 Dec 1998) |
| cis trans test | <molecular biology> The complementation test with two or more interacting genes placed in cis and in trans relationships to each other. A double mutant genome is used in the cis test made from the two single mutant genomes used in the trans test by recombination. If the wild type phenotype is restored by both cis and trans arrangements it is concluded that the two mutations are in different genes and hence that the phenotype is determined by more than one gene. If the trans test is negative and the cis positive this means that the two mutations are in the same gene. If both tests are negative then at least one of the mutations must be dominant. Thus the double test provides a means of fine mapping of genes. A lab test which is used to determine whether two mutations of different genes which affect the same phenotype are on the same functional unit (indicating a cis configuration of the mutated genes) or on different functional units (indicating a trans configuration of the mutated genes). (A functional unit can be a chromosome.) The test is done by mating an individual that has one of the mutations to an individual that has the other one, and observing whether their offspring have the mutant phenotype. If the offspring do not have the mutant phenotype, then the genes are known to be trans, because the offspring have normal copies of each mutant gene on the different functional units which are able to genetically complement each other. If the offspring do have the mutant phenotype, then the genes are known to be cis, because the offspring will always inherit at least one of the mutant genes on the one functional unit, resulting in the mutant phenotype. (09 Oct 1997) |
| 11-cis-retinal | The isomer of retinaldehyde that can combine with opsin to form rhodopsin; it is formed from 11-trans-retinal by retinal isomerase. Synonym: neoretinal b. (05 Mar 2000) |
| 11-cis-retinol | Retinol with cis configuration at the 11-position (carotenoid numbering) or 5'-position (retinol numbering) of the side chain; an intermediate in the vision cycle. Synonym: neoretinene B. (05 Mar 2000) |
| 9-cis-retinol dehydrogenase | <enzyme> Catalyses oxidation of 9-cis-retinol to 9-cis-retinaldehyde; does not catalyze oxidation of all-trans-retinol; genbank u89717 Registry number: EC 1.1.1.- Synonym: retinol dehydrogenase (9-cis) (26 Jun 1999) |